WO2022079371A1

WO2022079371A1 - Fuel supply circuit for a combustion chamber of a turbomachine

Info

Publication number: WO2022079371A1
Application number: PCT/FR2021/051727
Authority: WO
Inventors: Kevin Didier Pierre LE NORMAND; Frédéric Brettes; Loïc PORA
Original assignee: Safran Aircraft Engines
Priority date: 2020-10-14
Filing date: 2021-10-05
Publication date: 2022-04-21
Also published as: FR3115075A1; CN116324143A; EP4229288A1; US11905885B2; US20230407792A1; WO2022079372A9; EP4229287A1; FR3115075B1; US20230392550A1; WO2022079372A1; CN116324142A

Abstract

The present invention relates to a fuel supply circuit (1) comprising a supply duct (20) in which a first flow (F1) is able to circulate, at least one supply pump (3, 5) for circulating the fuel from a tank (2) to a metering unit (6), and a recirculation duct (60) for a second flow (F2) upstream of the pump (5), wherein the ducts (20, 60) discharge in different directions (D1, D2) upstream of the pump (5); the circuit (1) comprises a dispensing device (8) comprising an internal flow duct (800) for the first flow (F1), an external flow channel (820) for the second flow (F2) and at least one passage orifice (810) for the second flow (F2), which communicates fluidically with the channel (820); and the at least one orifice (810) and the duct (800) are coaxial and respectively discharge upstream of the pump (5).

Description

DESCRIPTION

TITLE: FUEL SUPPLY CIRCUIT FOR A TURBOMACHINE COMBUSTION CHAMBER

Technical field of the invention

The present invention relates to a fuel supply circuit for a combustion chamber, in particular equipped with a fuel flow distribution device intended for their mixing. The invention also relates to a turbomachine supplied via this fuel circuit and in particular an aircraft turbomachine.

Technical background

A turbomachine, in particular for an aircraft, comprises a gas generator comprising in particular one or more compressors, for example low pressure and high pressure, arranged upstream of a combustion chamber.

Traditionally, the combustion chamber is supplied with compressed air coming from the high pressure compressor via in particular an annular diffuser, and with fuel via a fuel supply circuit comprising injectors distributed angularly around a longitudinal axis of the turbomachine.

The fuel circuit may include the following elements mentioned here in the direction of the flow of fuel from upstream to downstream:

- a fuel tank for fuel storage,

- a BP low pressure pump to supply fuel from the tank,

- a fuel filtration unit to limit (or even eliminate) the elements contaminating the fuel at the outlet of the LP pump,

- an HP high pressure pump,

- a metering unit, usually called FMU (for “Fuel Metering Unit” according to English terminology), and

- a set of injectors delivering the total flow of fuel into the combustion chamber of the turbomachine. In general, the LP and HP pumps can be integral and be driven by the same output shaft of an accessory box, of the AGB type (for "Accessory GearBox" according to English terminology), of the turbomachine.

The LP pump allows fuel to be routed to the HP pump which supplies the fuel metering unit with a flow greater than the fuel requirement of the combustion chamber.

Figure 1 schematically illustrates the flow (or flow) of fuel injected by the HP pump of the supply circuit as a function of the speeds of the combustion engine of the turbomachine. The linear curve Ci represents a regular increase in the fuel flow supplied by the HP pump between the operating speeds Ri and R2 of the turbomachine. The regime Ri represents the fuel flow at the time of start-up or during the auto-rotation phase (or “Windmilling” according to English terminology) in flight or on the ground of the turbomachine. The speed R2 represents the fuel flow at a maximum normal operating speed of the turbine engine (such as at the time of takeoff of the aircraft). Curve C2 represents the fuel requirement of the combustion chamber to operate at speeds Ri and R2. This curve C2 represents a fuel flow meeting the needs of the combustion chamber which is much lower than the fuel flow injected by the HP pump of curve Ci. The quantity of excess fuel is represented by an arrow E in FIG. 1 .

This excess amount of fuel is recirculated through the fuel system. For this, the circuit also includes a recirculation channel configured to return from the FMU metering unit to an inlet of the HP pump, a second flow of fuel corresponding to the excess fuel quantity of the metering unit.

Thus, the first flow and the second flow of fuel mix before entering the HP pump. The outlet of the recirculation channel is generally close to the fuel inlet of the HP pump, in particular to optimize the size and the space in the turbomachine. This configuration has the main drawback that the first and second fuel flows entering the HP pump are not perfectly homogenized. This can cause cavitation (i.e. bubbles) in the fuel flow supplying the HP pump and which can damage the latter. Thus, the performance of the HP pump can be degraded and its lifetime limited.

It is known from the prior art a fuel supply circuit for a combustion chamber of an aircraft turbine engine comprising a loop for recirculating an excess quantity of fuel coming from a metering unit to a tank of fuel or a jet pump arranged upstream of an HP pump, as described respectively in the documents FR-A1 -2999653 and W0-A1 -2014/096620. When the fuel is returned to the tank, the question of the homogenization of the fuel upstream of the HP pump does not arise. As regards the jet pump, this is capable of mixing the first flow of fuel coming from a LP pump and the second flow coming from the metering unit to supply fuel to the HP pump. However, the jet pump has the disadvantage of requiring complicated and cumbersome assembly.

In this context, it is advantageous to overcome the drawbacks of the prior art, by proposing a reliable device for distributing several fuel flows which can be integrated into a fuel supply circuit of a combustion chamber, while allowing its simple and quick assembly in a turbomachine.

Summary of the invention

The invention proposes a fuel supply circuit for a combustion chamber of a turbomachine, in particular an aircraft, comprising:

- a supply channel configured for the circulation of a first flow of fuel coming from a fuel tank;

- a metering unit configured to supply a predetermined flow of fuel into the combustion chamber;

- at least one supply pump intended to circulate the fuel from the tank to the metering unit;

- a recirculation channel for a second flow of fuel, corresponding to an excess quantity of fuel coming from the metering unit, upstream of the supply pump; - the feed and recirculation channels opening out in different directions upstream of the feed pump.

According to the invention, the circuit comprises a device for distributing at least one of the fuel flows which comprises an internal conduit for the flow of the first fuel flow, an external annular groove for the flow of the second fuel flow and at least a passage orifice for the second flow which is in fluid communication with the annular groove.

According to the invention, said at least one orifice and said internal duct are coaxial and emerge respectively upstream of the feed pump.

Thus, this solution achieves the above objective. Indeed, such a configuration makes it possible to separate at least two fuel flows coming from different directions and to orient them in the same direction by means of the distribution device of the invention. This makes it possible to achieve a homogeneous and optimal mixture of these flows to emerge in the supply pump of the fuel supply circuit for a combustion chamber.

In particular, the fuel flows entering the distribution device have different flow rates and therefore come from distinct and intersecting channels upstream of the device (and consequently upstream of the supply pump). These flows entering the device are regulated by coaxial flow ducts (namely the internal flow duct of the first flow and the at least one passage orifice of the second flow), so that the flows do not not interfere with each other to form turbulence and/or cavitations. Thus, the flows leaving the distribution device have the advantage of having a stable flow rate and therefore of being in a state of rest. In this way, the flows at a stable flow mix at the outlet of the distribution device to emerge in the supply pump by a homogeneous mixture and without cavitation. The supply pump of the circuit of the invention is therefore not damaged by the fuel flows coming from the supply and recirculation channels of the circuit. Thus, the service life and performance of the fuel pump are greatly improved. The invention thus has the advantage of proposing a simple design, offering very high reliability, and not very penalizing in terms of cost and size of the turbomachine.

The fuel supply circuit according to the invention also comprises one or more of the following characteristics, taken alone or in combination:

- the supply channel opens downstream into the internal flow conduit of the distribution device and the recirculation channel opens into the annular groove of the distribution device;

- the device is mounted in a housing arranged upstream of the feed pump, and in which said at least one orifice and said internal duct open into a mixing zone of the housing;

- the supply and recirculation channels are configured to open secantly into the housing, in which a downstream end of the supply channel opens into the internal duct and an upstream end of the recirculation channel opens into the external annular groove;

- the downstream end of the supply channel opening into the internal flow duct, extends substantially axially or inclined with respect to axis A;

- the upstream end of the recirculation channel opening into the annular groove, extends substantially perpendicular or inclined with respect to axis A;

- the dispensing device comprises a main body of revolution extending around a longitudinal axis and comprising:

■ the internal flow duct of the first fuel flow which extends through the main body along the axis A, and

■ a first annular portion configured to form an outlet passage for the second fuel flow, and the first annular portion comprising said at least one second fuel flow passage orifice which is distributed according to an annular row of orifices around the axis;

- Said at least one orifice extends along an axis parallel to the axis of the internal duct; - said internal flow conduit and said at least one orifice are configured to open out transversely to an axis around which the feed pump extends;

- the main body further comprises a second annular portion configured to form an inlet passage for the first flow of fuel through the internal duct, the second portion is connected to the first portion via an intermediate portion delimiting at least in part the central opening;

- the second portion further comprises at least one annular sealing and fixing groove configured for mounting a sealing element;

- the fuel circuit supply pump comprises a low-pressure pump (for example of the rotodynamic type) and/or a high-pressure pump (for example of the positive-displacement type with gears);

- the housing and the mixing zone are arranged upstream of the high pressure pump;

- the internal conduit for the flow of the first fuel flow is formed by a central opening.

The present application also relates to a turbomachine, in particular for an aircraft, comprising a fuel supply circuit according to one of the features of the invention, for a combustion chamber of the turbomachine.

The invention also proposes a device for distributing at least one flow of fuel for a fuel supply circuit of a combustion chamber of a turbine engine, in particular an aircraft, the device comprising a main body of revolution extending around a longitudinal axis A. The main body comprises:

- an internal conduit for the flow of a first fuel flow and extending through the main body along the axis A, and

- A first annular portion configured to form an outlet passage for the second fuel flow, and comprising at least one passage orifice for the second fuel flow. The dispensing device according to the invention has the advantage of ensuring several functions within the fuel supply circuit, namely:

- guide the first flow of fuel coming from a supply channel of the circuit (for example from a first filtration unit with reference to the example described below or from a low pressure pump);

- guide the second flow of fuel coming from a circuit recirculation channel;

- orient the first and second flows in the same direction (in particular via the coaxial flow ducts);

- seal the housing arranged in at least one of the casings of the fuel circuit components (for example between the casings of the first filter unit and a high pressure pump with reference to the example described below).

In addition, as described in the foregoing, the distribution device fitted to the fuel circuit therefore makes it possible to dissociate the first flow and the second flow coming from channels of different directions, and to orient them in the same direction at the outlet of the device. . This makes it possible to slow down the flow rate of each of the fuel flows, so as to limit (or even eliminate) turbulence and/or cavitations in the fuel leaving the device. In this way, the flow of fuel entering a supply pump of the circuit is optimally homogenized, in particular after passing through a mixing zone located between the supply pump and the device.

The dispensing device according to the invention also comprises one or more of the following characteristics, taken alone or in combination:

- the device comprises an outer annular groove which is in fluid communication with the at least one orifice of the first portion;

- said at least one orifice for passage of the second fuel flow is distributed according to an annular row of orifices;

- the annular row of orifices each extends along an axis parallel to axis A;

- the main body further comprises a second annular portion configured to form an inlet passage for the first flow of fuel through the internal duct;

- The second portion is connected to the first portion via an intermediate portion of the dispensing device delimiting at least in part the internal duct; - The second portion comprises an annular flange extending radially around the axis A;

- the annular groove is delimited at least in part by a side of the flange and a first portion wall;

- The first annular portion has an outer diameter smaller than the outer diameter of the annular collar of the second annular portion;

- each orifice of the annular row of orifices has a diameter of between 3 and 10 mm, preferably between 5 and 7 mm, and more preferably around 5.5 mm;

- the annular row of orifices comprises between five to twenty orifices, preferably between fifteen and twenty orifices, and even more preferably about seventeen orifices.

The present application also relates to a turbine engine, in particular for an aircraft, comprising a device for distributing at least one flow of fuel according to one of the features of the invention, for a fuel supply circuit of a turbomachine combustion chamber.

Brief description of figures

The invention will be better understood and other details, characteristics and advantages of the invention will appear more clearly on reading the following description given by way of non-limiting example and with reference to the appended drawings in which:

[Fig. 1] Figure 1 is a schematic graph illustrating the fuel flow supplied by a high pressure pump of a fuel supply circuit and the fuel flow required by a combustion chamber;

[Fig. 2] Figure 2 is a very schematic view of a fuel supply circuit for a combustion chamber of a turbomachine according to the invention;

[Fig. 3] Figure 3 is a schematic perspective view of the upstream side of a device for distributing at least one fuel flow of the circuit of Figure 2;

[Fig. 4] Figure 4 is a schematic perspective view of the downstream side of the dispensing device of Figure 3; [Fig. 5] Figure 5 is a schematic sectional view of the dispensing device of Figure 4; and

[Fig. 6] Figure 6 is an enlarged schematic view in section of the arrangement of the distribution device of Figures 3 to 5 in the power supply circuit of Figure 2.

Detailed description of the invention

By convention, in the description below, the terms “longitudinal” and “axial” qualify the orientation of structural elements extending along the direction of a longitudinal axis X. This axis X can be confused with an axis of rotation of a rotor of a turbomachine. The terms “radial” or “vertical” qualify an orientation of structural elements extending in a direction perpendicular to the X axis. The terms “interior” and “exterior”, and “internal” and “external” are used in reference to a positioning relative to the X axis. Thus, a structural element extending along the X axis has an inner face facing the X axis and an outer surface, opposite its inner surface. In the present application, the terms “upstream” and “downstream” are defined with respect to the direction of circulation of the gases in the turbomachine.

Figure 1 has been described above.

The invention applies to a turbomachine 100, in particular an aircraft, comprising a gas generator or motor. Such a turbomachine can be a turboprop, a turbojet or a turbine engine. The gas generator of the turbomachine typically comprises one or more compressors, for example low pressure and high pressure, arranged upstream of a combustion chamber 9.

The combustion chamber 9 is supplied with compressed air coming from the high pressure compressor via in particular an annular diffuser, and with fuel via a fuel supply circuit 1 comprising injectors distributed angularly around a longitudinal axis X of the turbomachine.

The fuel supply circuit 1 (or fuel circuit 1 in the present application) of FIG. 2 may comprise the following elements cited here in the direction of the flow of the fuel from upstream to downstream:

- a fuel tank 2 for fuel storage, - a low pressure pump BP 3, for example of the rotodynamic type (such as a centrifugal pump making it possible to pump and evacuate a fluid by rotation of a rotor or a propeller wheel) to ensure the fuel supply from tank 2,

- a first fuel filtration unit 4a to limit (or even eliminate) the elements contaminating the fuel at the outlet of the LP pump 3,

- an HP 5 high-pressure pump, for example of the volumetric type with gears,

- a second fuel filtration unit 4b to limit (or even eliminate) the elements contaminating the fuel at the outlet of the HP pump 5,

- a metering unit 6 to output a total flow of fuel distributed to the combustion chamber 9, and

- a set of injectors 7 delivering a total flow of fuel into the combustion chamber 9 of the turbomachine 100.

The LP 3 and HP 4 pumps can be integral and be driven by the same output shaft of an accessory box (not shown in the figure), for example of the AGB type, of the turbomachine 100. This in particular makes it possible to adapt the flow sent by the LP 3 and HP 5 pumps to the needs of the combustion chamber 9.

The LP pump 3 supplies the first filtration unit 4a and the HP pump 5 with a first flow of fuel F1 coming from the tank 2 via a supply channel 20. The HP pump 5 supplies the second unit of filtration 4b and the fuel metering unit 6, for example via the supply channel 20, with a higher flow rate than the fuel requirement of the combustion chamber 9.

As described above, a quantity of excess fuel is recirculated in the fuel circuit 1 via a recirculation channel 60. This recirculation channel 60 is configured to return upstream of the pump HP 5, a second fuel flow F2 corresponding to the amount of excess fuel from metering unit 6.

Thus, the first flow F1 and the second flow F2 of fuel mix before entering the HP pump 5.

In the example of Figure 2, the channels 20, 60 open out in different directions D1, D2 (illustrated in Figure 6) upstream of the HP pump 5. One of the particularities of the invention resides in the fact that the fuel circuit 1 also comprises a device 8 for distributing fuel. This dispensing device 8 can be removably assembled upstream of the HP pump 5.

In Figure 2 and in a non-limiting manner, the dispensing device 8 is located in a housing 10 of the circuit 1. The device 8 and the housing 10 are located downstream of the first filtration unit 4a and upstream of the pump HP 5. The housing 10 may have a general shape at least partially complementary to the general shape of the dispensing device 8.

In the case of the fuel circuit 1, the distribution device 8 is configured to channel and ensure a homogeneous mixture of the first F1 and second F2 fuel flows coming, respectively, from the supply channel 20 and the recirculation channel 60 .

Channels 20, 60 are configured to open secantly into housing 10 (and therefore into device 8).

Furthermore, the housing 10 comprises a zone 12 for mixing the fuel flows F1, F2 leaving the distribution device 8. In FIG. 2, the mixing zone 12 is located downstream of the distribution device 8 and upstream of the HP pump 5.

With reference to Figures 3 to 5, we will now describe the fuel distribution device 8 fitted to the fuel circuit 1.

The distribution device 8 has a shape of revolution extending around a longitudinal axis A. The axis A can be substantially parallel or inclined with respect to the axis X of the turbomachine 100. The distribution device 8 comprises a main body 80 of generally elongated shape and extending around the axis A.

In the example of Figures 3 to 5, the main body 80 comprises a first annular portion 81, a second annular portion 83 which is opposite (along the axis A) to the first portion 81, and an intermediate portion 82 which connects the annular portions 81, 83 between them. Advantageously, the portions 81, 82, 83 are formed in one piece (made from the material).

The main body 80 further comprises an internal flow duct 800 extending along the axis A. This internal duct 800 may have a cylindrical shape. The conduit internal 800 can be formed by a central and through opening. In the example, the opening of the internal duct 800 has a circular cross section. The opening of the internal duct 800 can have a diameter Ds00 of between 10 and 50 mm, preferably between 20 and 30 mm. Even more preferentially, the diameter Ds00 is around 26 mm. In Figure 3, the central opening 800 has a length L1 substantially between 20 and 50 mm. Advantageously, the length L1 is between 25 and 30 mm.

In the example, the opening of the internal duct 800 forms a fuel inlet passage which is located on the side of the second portion 83 and a fuel outlet passage which is located on the side of the first portion 81 . More particularly, the opening of the internal duct 800 opens onto a front wall 812 of the first portion 81 and a rear wall 832 of a rear end 830 of the second portion 83.

The first portion 81 comprises the front wall 812 and a rear wall 814 which are substantially transverse to the axis A. The front wall 812 passes substantially through a plane P1 and the rear wall 814 passes substantially through a plane P2. In Figures 3 and 4, the planes P1 and P2 are substantially perpendicular to the axis A. Furthermore, in the example, the first portion 81 has an annular outer surface which is narrowed in the direction of the plane P2.

The first portion 81 further comprises at least one orifice 810. This orifice 810 is configured for the passage of fuel. In the example of Figures 3 to 5 and in a non-limiting manner, the first portion 81 comprises an annular row of orifices 810 extending circumferentially around the axis A. Each of the orifices 810 of the annular row of orifices is through and extends axially between the planes P1 and P2. In FIG. 4 and without limitation, the length L2 between the planes P1 and P2 (substantially corresponding respectively between the front wall 812 and the rear wall 814) is between 5 and 15 mm, preferably around 8 mm . Each of the orifices 810 can also extend substantially parallel to the central opening of the internal duct 800. The annular row of orifices comprises between five to twenty orifices, preferably between fifteen and twenty orifices. More preferably, there are approximately seventeen orifices. Each orifice 810 of the annular row of orifices has a diameter Ds of between 3 and 10 mm, of preferably between 5 and 7 mm, and even more preferably about 5.5 mm. The opening of the internal duct 800 and the orifices 810 are coaxial, in particular with respect to the axis A. The first portion 81 is configured to form a fuel outlet passage. The annular array of ports is configured to form both a fuel inlet passage and a fuel outlet passage.

The intermediate portion 82 delimits between the first 81 and second 83 portions an annular groove 820. Thus, in the example, the annular groove 820 extends from front to rear between the plane P2 and a plane P3. The plane P3 is substantially parallel to the planes P1 and P2. In FIG. 3 and in a non-limiting manner, the length L3 between the planes P1 and P3 (substantially corresponding respectively between the front wall 812 of the first portion 81 and one end of the intermediate portion 82 which is opposite the wall 812) is between 15 and 30 mm, preferably about 21 mm. This annular groove 820 is in fluid communication with the orifices 810 of the first portion 81. The annular groove 820 is configured to form a fuel inlet passage.

The second portion 83 comprises an annular collar 84 extending radially outwards and around the axis A. The annular collar 84 is located on the side of the intermediate portion 82. The annular collar 84 has a front side 842 and a rear flank 844 which is axially opposite front flank 842. Flanks 842, 844 are connected by a peripheral annular surface 843. In the example, front flank 842 is defined substantially in plane P3.

The second portion 83 also comprises at least one annular groove 85, called sealing and fixing, extending around the axis A. The annular sealing and fixing groove 85 is configured for the mounting of an element sealing 850. In particular, in the example, this has an axial U-section and opens onto the annular peripheral surface 843. Advantageously, this sealing element 850 is an O-ring (illustrated in FIG. 6) . Similarly, in the example, the rear end 830 may also include the annular groove 85 which may have a U-shaped axial section and lead to an annular peripheral surface of the rear end 830. In FIG. 5, the second portion 83 comprises two annular grooves 85 arranged, respectively, on the annular collar 84 and on the rear end 830 which is opposite (along the axis A) to the annular collar 84. In the example, the annular flange 84 has an outer diameter Ds4 (delimited by the outer peripheral surface 843) greater than the outer diameter of the rear end 830 of the second portion 83.

The second portion 83 is configured to form a fuel inlet passage.

In the example, the outer diameter Ds4 of the annular collar 84 is greater than the outer diameter Dsi of the first portion 81. The outer diameter Dsi of the first portion 81 is greater than the outer diameter Ds2o of the annular groove 820.

We will now describe the distribution device 8 equipped in the fuel circuit 1 of the invention.

With reference to Figures 2 and 6 and without limitation, the dispensing device 8 is assembled in the housing 10 arranged downstream of the first filter unit 4a and upstream of the HP pump 5.

The HP 5 pump can be of the positive-displacement gear type. In this case, the HP pump 5 may comprise one or more toothed wheels 52. The toothed wheel 52 has an axis of rotation B, as illustrated in FIG. 6. This axis B is substantially perpendicular to the axis A of the device 8.

The housing 10 has a generally cylindrical shape extending along an axis of revolution. In FIG. 6, this axis of revolution of the housing 10 substantially coincides with the axis A of the dispensing device 8. The housing 10 can be formed by the walls of at least one of the casings 40, 50 and/or at least least one of the channels 20, 60 of the fuel circuit 1. In the example and in a non-limiting manner, the housing 10 is located at least in part between the casings 40, 50 of the first filter unit 4a and of the HP pump 5. In FIG. 6, the housing 10 emerges at the less partly radially in the recirculation channel 60. In addition, the housing 10 opens upstream into the supply channel 20 and downstream into the mixing zone 12 of the fuel circuit 1 .

The mixing zone 12 has a generally annular or cylindrical shape. In the example, this mixing zone 12 can also extend along a longitudinal axis which coincides with the axis of revolution of the housing 10 and the axis A of the dispensing device 8. In FIG. 6, the mixing zone 12 thus opens upstream into the housing 10 (and also the first portion 81 of the dispensing device 8 installed in the housing 10), and downstream into the HP pump 5 (for example in the gears of the cogwheel 52 of the HP pump 5).

In FIG. 6, the front wall 812 of the first portion 81 of the dispensing device 8 bears against an upstream wall 102 of the housing 10. In the example, the housing 10 may correspond to a wall of the casing 50 of the HP pump 5. The front side 842 of the annular flange 84 of the dispensing device 8 bears against a downstream wall 104 of the housing 10. In the example, the casing 40 of the first filter unit 4a bears the downstream wall 104 .

In the example, O-rings 850 are installed between the grooves 85 of the dispensing device 8 and the internal annular surfaces of the casings 40, 50. These O-rings are sufficient to hold the dispensing device 8 in a fixed and sealed manner in the housing 10.

The supply channel 20 of the circuit 1 comprises an upstream outlet 22 which opens into the central opening 800 on the side of the second portion 83, upstream of the distribution device 8. The upstream outlet 22 is oriented in a direction extending substantially inclined or axial with respect to the axis A.

The recirculation channel 60 of the circuit 1 comprises an upstream outlet 62 opening out into the housing 10, in particular into the annular groove 820 of the intermediate portion 82. The downstream outlet 62 is oriented in a direction extending substantially transversely with respect to the axis A. In particular, the exit direction is perpendicular or inclined (with an angle between 20 and 50°) with respect to axis A.

Referring to Figure 6, the first flow of fuel F1 comes from the supply channel 20 in a first direction D1, and the second flow of fuel F2 comes from the recirculation channel 60 in a second direction D2.

The first flow of fuel F1 passes through the central opening of the duct 800 of the distribution device 8 to emerge in the mixing zone 12 then in the HP pump 5. This allows the first flow F1 to flow inside and exit from the dispensing device 8 along a third direction D3. This third direction D3 is coaxial with the axis A and also with the axes of revolution of the mixing zone 12 and of the housing 10. The flow direction D3 of the first flow F1 can be different from the first direction D1 when the upstream outlet 22 opens in an inclined manner with respect to the axis A (as illustrated in figure 6), or coaxial with the direction D1 when the upstream outlet 22 opens axially to the axis A.

Advantageously, the first flow F1 in the third direction D3 emerges substantially perpendicular to the axis B of the toothed wheel 52 of the HP pump 5.

The walls formed in the housing 10, by the upstream end 62 and the annular groove 820, form an annular chamber 826 in which the second flow of fuel F2 enters the distribution device 8. The second flow F2 then passes through the orifices 810 of the first portion 81 to open into the mixing zone 12 then into the HP pump 5. This allows the second flow F2 to flow inside and at the outlet of the distribution device 8 also in the third direction D3 . In the example, this flow direction D3 of the second flow F2 is different from the second direction D2.

In the annular chamber 826, the second flow F2 is braked with respect to its speed in the recirculation channel 60. This allows the second flow F2 to pass from a turbulent state in the recirculation channel 60 to a laminar state in the orifices 810, then into mixing zone 12.

We understand that the distribution device of the invention is located at the confluence of the outputs of the first and second flows F1, F2 and that the flows mix at the output of the distribution device.

Thus, the fuel flows F1, F2 emerging in the mixing zone 12 do not present or have very few cavitations before entering the HP pump 5. In the mixing zone 12, the fuel flows F1, F2 are made homogeneous for their flows in the HP 5 pump.

In the present application, the distribution device is described for the distribution or channeling of fuel for a fuel supply circuit of a combustion chamber of a turbomachine, in particular an aircraft. The device for distributing the invention can also be adapted for any type of fluid and for hydromechanical turbomachine systems other than the field of aeronautics.

The fuel distribution device fitted to the fuel supply circuit according to the invention provides several advantages which are in particular:

- optimize the mixing and homogenization of the fuel flows coming from the intersecting and non-coaxial supply and recirculation channels, upstream of the supply pump,

- propose a distribution and mixing device within the size and available space of the fuel circuit,

- optimize the service life of the supply pump by preventing the formation of cavitations in the fuel,

- attach and detach easily from the power supply circuit,

- limit the maintenance cost of a fuel circuit supply pump, and

- easily adapt to existing gas generators.

Overall, this proposed solution is simple, effective and economical to produce and to assemble on a turbomachine, while ensuring optimum fuel supply and improved service life of at least one of the components of a fuel supply circuit for a combustion chamber of a turbomachine.

Claims

1. Fuel supply circuit (1) for a combustion chamber (9) of a turbine engine (100), in particular an aircraft, comprising:

- a supply channel (20) configured for the circulation of a first flow of fuel (F1) coming from a fuel tank (2);

- a metering unit (6) configured to supply a predetermined flow of fuel into the combustion chamber (9);

- at least one supply pump (3, 5) intended to circulate the fuel from the tank (2) to the metering unit (6);

- a recirculation channel (60) for a second fuel flow (F2), corresponding to a quantity of excess fuel coming from the metering unit (6), upstream of the supply pump (5);

- the supply and recirculation channels (20, 60) opening out in different directions (D1, D2) upstream of the supply pump (5); characterized in that the circuit (1) comprises a device (8) for distributing at least one of the fuel flows (F1, F2) which comprises an internal duct (800) for the flow of the first fuel flow (F1) , an outer annular groove (820) for the flow of the second fuel flow (F2) and at least one orifice (810) for the passage of the second flow (F2) which is in fluid communication with the annular groove (820), and that said at least one orifice (810) and said internal duct (800) are coaxial and open respectively upstream of the supply pump (5).

2. Circuit (1) according to claim 1, characterized in that the device (8) is mounted in a housing (10) arranged upstream of the supply pump (5), and wherein said at least one of orifice (810) and said internal duct (800) open into a mixing zone (12) of the housing (10).

3. Circuit (1) according to claim 1 or 2, characterized in that the supply channel (20) opens downstream into the internal flow conduit (800) of the distribution device (8) and the recirculation channel (60) opens into the annular groove (820) of the dispensing device (8).

4. Circuit (1) according to claim 2, characterized in that the supply and recirculation channels (20, 60) are configured to open secantly into the housing (10), in which a downstream end (22) of the supply channel (20) opens into the internal duct (800) and an upstream end (62) of the recirculation channel (60) opens into the external annular groove (820).

5. Circuit (1) according to claim 4, characterized in that the downstream end (22) of the supply channel (20) opening into the internal flow duct (800) extends substantially axially or inclined with respect to the axis (A).

6. Circuit (1) according to claim 4, characterized in that the upstream end (62) of the recirculation channel (60) opening into the annular groove (820) extends substantially perpendicular or inclined with respect to the axis (A).

7. Circuit (1) according to one of claims 1 to 6, characterized in that the distribution device (8) comprises a main body (80) of revolution extending around a longitudinal axis (A) and comprising :

- the internal conduit (800) for the flow of the first fuel flow (F1) which extends through the main body (80) along the axis (A), and

- a first annular portion (81) configured to form an outlet passage for a second fuel flow (F2), and the first annular portion (81) comprising said at least one orifice (810) for passage of the second fuel flow (F2) which is distributed along an annular row of orifices (810) around the axis (A).

8. Circuit (1) according to claim 7, characterized in that each orifice (810) extends along an axis parallel to the axis (A) of the duct (800) internally.

9. Circuit (1) according to one of claims 1 to 8, characterized in that said internal flow conduit (800) and said at least one orifice (810) are configured to open out transversely to an axis (B ) around which extends the feed pump (5).

10. Circuit (1) according to one of claims 7 to 9, characterized in that the main body (80) further comprises a second annular portion (83) configured to form an inlet passage for the first fuel flow ( F1) through the conduit (800) internal, the second portion (83) is connected to the first portion (81) via an intermediate portion (82) delimiting at least in part the central opening.

11. Circuit (1) according to claim 10, characterized in that the second portion (83) further comprises at least one annular sealing and fixing groove (85) configured for mounting a sealing element ( 850).

12. Circuit (1) according to one of claims 1 to 11, characterized in that the supply pump (3, 5) is a low-pressure pump (3), for example of the rotodynamic type, and/or a pump high pressure (5), for example of the volumetric type with gears.

13. Circuit (1) according to claim 12, characterized in that the housing (10) and the mixing zone (12) are arranged upstream of the high pressure pump (5).

14. Circuit (1) according to one of claims 1 to 13, characterized in that the conduit (800) internal flow of the first fuel flow (F1) is formed by a central opening.

15. Aircraft turbomachine (100), comprising a fuel supply circuit (1) according to one of claims 1 to 14, for a combustion chamber (9) of the turbomachine (100).